If we have a (steady-state) incompressible, nonviscous fluid, we are interested in finding its velocity field [math]V(x,y).[/math] If [math]F=\phi+i\psi[/math] is the complex potential, the functions [math]\phi[/math] and [math]\psi[/math] are the [b]velocity potential[/b] and [b]stream[/b] functions, respectively. In this case [math]V=\text{grad}\,\phi[/math].
